Field of the Invention
This invention is in the field of mechanical fasteners, more particularly in the field of threaded fasteners, and still more particularly in the field of fasteners exposed to the elements or other corrosive conditions.
Description of the Related Art
A very common fastener is the combination of a threaded nut and bolt. After a nut is fastened onto a bolt (or a threaded stud) and left exposed to air, their surfaces become corroded over an amount of time dependent on the material they are made of, the amount of moisture in the air, and the presence of electrolytes such as salts. After corrosion occurs, the amount of torque necessary to loosen the nut from the bolt can become significantly greater than that used to tighten the nut in the first place.
Conditions for such corrosion are commonly found in the environment of vehicle wheel lug nuts and the threaded studs (lugs) onto which they are tightened. Moist air and salts easily access the lugs and lug nuts even when wheel covers or hub caps are in place. The result is that by the time it is necessary to loosen the lug nuts for tire rotation, the impact wrenches used can crack the studs or nuts, creating the possibility of mechanical failure at high speed.